In Setúbal Peninsula, in the foothills east of the Arrábida mountains, is situated between the estuaries of the River Tagus and Sado river, near the mouth of the latter. Is part of the so-called Riviera, in the Arrábida Natural Park. On a clear day from the top of the castle one can see Lisbon.

During  the Christian Reconquest of the Iberian peninsula after the conquest of Lisbon (1147) by the forces of King Afonso Henriques (1112-1185), 3 cities have fallen in to the Portuguese domain : Sintra, Almada and Palmela.

At the time, the Muslim forces defending Palmela, abandoned it, and took  refuge in Alcácer do Sal. And the Portuguese forces only conquered the village and its domains. Muslim forces, however, soon reorganized, recovering south of the Tagus river. Christians reconquered Palmela in 1158.

Again lost, was finally conquered on June 24 1165. From the following year reinforcement works were undertaken.

The presence of man in what is now occupied by the city of Palmela dates back to the Neolithic era, where their presence is quite noticeable, especially during the bell culture, and whose testimony left us in the form of the internationally renowned Palmela vase.

Occupied by Celts, Romans and Arabs, all found in this territory a strategic place to settle. In 1147 it was conquered by D. Afonso Henriques, granting it a charter in 1185. But the golden period of Palmela can be found in the early years of the Nationality, when Palmela was the key of the territory between the Sado and Tagus.

This strategic importance due to situational aspects of political and religious nature related to the process of conquest and consolidation of the Portuguese State, and which the Order of Santiago and Sword, (which received Palmela as a gift of D. Afonso Henriques around 1172), can not be separated. The Order of Santiago mark its presence in Portuguese society to be lady of a vast region from the ancient city of Riba Tejo (which includes the current municipalities of Barreiro, Moita, Montijo and Alcochete) to Mértola, in the Alentejo. The Order’s administrative power was centered in Palmela. The importance of this choice is not held only with the proximity of Palmela face to Lisbon, where the congregation held the convent of Santos, among others, but also because  Palmela was the largest Commandery of the Order and the characteristics of its castle that accommodate the monumental complex of the Order – the Convent and the Church. Away from the dangers of invasions – Arab initially and Spanish at a later time – the Order of Santiago begins to lose importance and the power it held. Along with it, Palmela also no longer had the role of advanced guardian, a role previously played by the ancient Order’s headquarters – Mértola and Alcacer do Sal After the extinction of the Military and Religious Orders, Palmela no longer had any importance or strategic, or economic, or political, to the point that the Administrative Reform Mouzinho da Silveira in 1855, extinguished their municipality integrating it in Setúbal, where it will remain until 1926. Taking advantage of the military movement resulting from the May 28, 1926 , local elites press the government to restore access to the city of Palmela, a fact which is consummated in November of that year.